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1.
G. D. Griffin 《Journal of nematology》1983,15(3):426-432
Heterodera schachtii significantly (P = 0.05) reduced sugarbeet root growth below that of uninoculated controls at 20, 24, and 28 C, and Ditylenchus dipsaci significantly (P = 0.05) reduced root growth below that of uninoculated controls at 16, 20, 24, and 28 C. A combination of H. schachtii and D. dipsaci significantly (P = 0.05) reduced root growth below that of single inoculations of H. schachtii at all temperatures and D. dipsaci at 20, 24, and 28 C. Single inoculations of H. schachtii and D. dipsaci significantly (P = 0.05) reduced top growth of sugarbeet below that of uninoculated controls at 20, 24, and 28 C, and 16, 20, 24, and 28 C, respectively. A combination of the two nematodes significantly (P = 0.05) reduced top growth below that of single inoculations of H. schachtii at all temperatures. However, a combination of the two nematodes failed to significantly (P = 0.05) reduce top growth below that of single inoculations of D. dipsaci at any temperature. Inoculations of either H. schachtii or D. dipsaci did not affect penetration of the other nematode, and D. dipsaci did not affect development and reproduction of H. schachtii. D. dipsaci did not reproduce on sugarbeet. 相似文献
2.
R. N. Inserra G. D. Griffin N. Vovlas J. L. Anderson E. D. Kerr 《Journal of nematology》1984,16(2):135-140
Heterodera schachtii, Meloidogyne hapla, and Nacobbus aberrans either alone, or in various combinations with each other, can, when inoculated at a concentration of 12 second-stage juveniles/ cm³ of soil, cause a significant (P = 0.01) suppression of growth of sugarbeet (cv. Tasco AH14) seedlings. M. hapla and H. schachtii decreased growth of sugarbeet more than N. aberrans over a 60-day period. The adverse effect of N. aberrans on the final population/initial population (Pf/Pi) ratio for either M. hapla or H. schachtii was dependent on time, and was more accentuated on that of M. hapla than on that of H. schachtii. Neither M. hapla nor H. schachtii had an adverse effect on the Pf/ Pi ratio of N. aberrans. N. aberrans is considered to be less aggressive on sugarbeet than either H. schachtii or M. hapla. Sections of sugarbeet roots infected simultaneously with H. schachtii and N. aberrans showed scattered vascular elements between the N. aberrans syncytium located in the central part of the root and that of H. schachtii in the peripheral position. 相似文献
3.
G. D. Griffin 《Journal of nematology》1977,9(3):211-215
Soil moisture and the nematode population density in aldicarb-treated soil influenced control of the sugarbeet nematode, Heterodera schachtii. Greater numbers of nematode larvae infected 14-day-old sugarbeet seedlings growing in aldicarb-treated soil at 20-30% than at 80-100% field capacity (F. C.), and plant growth was inversely related to nematode infection and the nematode population density. Compared with that of control plants, plant growth increase also was greater at 80-100% F. C. when the nematode population was above 1.8 larvae/gm soil. A nematode population of 1.8 larvae/gm soil did not significantly affect sugarbeet yields. Aldicarb gave less control when soil moisture levels dropped to 20 and 50% F. C. at nematode populations of 3.5 and 6.2 larvae/gm soil. More effective control was obtained wth soil moisture levels at or above 80% F. C. This difference was attributed to continued activity of the toxicant in the rhizosphere at the high moisture level. 相似文献
4.
G. D. Griffin 《Journal of nematology》1981,13(2):180-184
Sugarbeet yields were contpared with field populations of Heterodera schachtii Schmidt. The correlation between sugarbeet yields and viable larvae/g of soil was negative and high, but that between sugarbeet yields and viable cysts/g of soil was lower. Sugarbeet yields were also compared with H. schachtii populations by years of rotation with a nonhost crop. The coefficients of correlation (r) between yield and viable larvae/g of soil were negative and high: 0 yr of rotation, -0.935; 1 yr, -0.922; 2 yr, -0.954; 3 yr, -0.935; and combined years, -0.965, with 95% confidence limits of -0.91 to -0.98 for combined years. The comparable correlation coefficients between yield and "viable cysts"/g of soil were negative and lower: 0 yr of rotation, -0.151; 1 yr, -0.022; 2 yr, -0.490; 3 yr, -0.456; and combined years, -0.586, with 95% confidence limits of -0.22 to -0.80 for the combined years. 相似文献
5.
Similar host ranges were found for Heterodera schachtii and a race of H. trifolii parasitic on sugarbeet in The Netherlands. Twenty-nine of 41 plant accessions evaluated were susceptible to H. trifolii. Five breeding lines of the interspecific hybrid Beta vulgaris-B. procumbens which are resistant to H. schachtii were highly susceptible to H. trifolii. An accession of B. maritima with partial resistance to H. schachtii was resistant to H. trifolii. 相似文献
6.
Arnold E. Steele 《Journal of nematology》1976,8(2):137-141
Treatment of sugarbeet, Beta vulgaris L., with aldicarb, aldicarb sulfoxide, or aldicarb sulfone 10 days after plants were inoculated with Heterodera schachtii prevented development of the nematode, but second-stage larvae penetrated the roots. These chemicals had no measurable effects on nematodes in plants treated 15 days after inoculation. The tests established that soil treatments of aldicarb are directly or indirectly lethal to larvae developing within roots of sugarbeet. Heterodera schachtii failed to develop on root slices of red table beet grown in soil treated with aldicarb or aldicarb sulfoxide. Similar treatment of plants with aldicarb sulfone or oxamyl did not affect subsequent development of H. schachtii on root slices of treated plants. 相似文献
7.
G. D. Griffin 《Journal of nematology》1981,13(2):184-190
There were direct relationships between inoculum density of Heterodera schachtii Schm. (nematode population density), initial soil temperature, the growth of sugarbeets in the greenhouse under controlled temperatures, and nematode populations. Heterodera schachtii was least pathogenic on plants inoculated at 6 wk of age and most pathogenic on plants grown from inoculated germinated seed (0 wk of age). In the field, H. schachtii was least pathogenic on sugarbeets grown at an initial soil temperature of 6 C and most pathogenic on those grown at an initial soil temperature of 24 C. The growth period for sugarbeets at the different soil temperatures was determined by heat units; since penetration of sugarbeet roots by H. schachtii larvae is accelerated at soil temperatures above 10 C, each hour-degree ahove 10 C was counted as one effective heat unit (HU). Using this guideline it was determined that root weight depressions in the greenhouse, for each degree-unit population (HU-UP) where unit population = one larvae/g soil, were 0.052, 0.09, 0.12, and 0.17 mg at initial soil temperatures of 6, 12, 18, and 24 C, respectively. Root weight depressions were 0.28, 0.23, 0.15, and 0.086 mg when plants were inoculated at 0, 2, 4, and 6 wk of age. 相似文献
8.
G. D. Griffin 《Journal of nematology》1981,13(2):191-195
Five populations of Heterodera schachtii Schm. from Oregon, Idaho, and Utah did not differ significantly in seedling penetration and rate of emergence and virulence. Another Utah H. schachtii population (Utah 2), however, differed from these five populations in all of the above-mentioned characteristics. More H. schachtii larvae of the Utah 2 population than the other populations penetrated sugarbeet seedlings at 10, 15, 20, and 25 C. Root and top weights of sugarbeet plants were signiticantly less when roots were parasitized by the Utah 2 population than when they were parasitized by larvae of the other nematode populations under similar experimental conditions. Also, the period of larval emergence was shorter in the Utah 2 population than in any of the other H. schachtii populations. 相似文献
9.
The host-parasite relationships between Heterodera schachtii Schm. and the nematode-resistant diploid Beta vulgaris L. line ''51501'' were examined via serial sections of secondary rootlets. Second-stage larvae penetrated sugarbeet roots and migrated up to 1.95 mm before establishing permanent feeding sites. Most sedentary larvae were oriented parallel to the root axis or in various diagonal or folded positions in the cortex. Nematodes adopted no definite orientation with regard to the root apex. Nematode feeding stimulated formation of multinucleate syncytia in host tissues. Syncytia were 0.3-1.1 mm in length, up to 90 [mu]m × 150 [mu]m in cross section. Root diameters were enlarged close to feeding sites. Usually nematodes deteriorated concomitant with necrosis of syncytia, and dead nematodes frequently appeared macerated or flattened and deformed. Most nematodes did not develop to maturity" in the resistant host tissues, Cavities left by collapse of syncytia were filled by growth of parenchymatous tissue. 相似文献
10.
E. P. Caswell A. E. MacGuidwin K. Milne C. E. Nelsen I. J. Thomason G. W. Bird 《Journal of nematology》1986,18(4):512-519
A simulation model of a single sugarbeet, Beta vulgaris L., plant infected by the sugarbeet cyst nematode, Heterodera schachtii Schmidt, was developed using published information. The model is an interactive computer simulation programmed in FORTRAN. Given initial population densities of the nematode at planting, the model simulates nematode population dynamics and the growth of plant tap and fibrous roots. The driving variable for nematode development and plant growth is temperature. 相似文献
11.
In two glasshouse experiments, relations between sugarbeet root dry weight (y, expressed as a percentage of the maximum dry root weight), and preplanting populations of Heterodera schachtii (Pi) were described by the equation y = 100(Z)Pi-T, in which Z = a constant slightly smaller than 1, and T = the tolerance limit (the value of Pi below which damage was not measureable). T varied with temperature; it was 65 eggs/100 g soil at 23 and 27 C and 430 eggs/100 g soil at 19 C. At 15 and 31 C there was no loss of root dry weight up to the maximum preplanting populations tested. In a field experiment in the Imperial Valley the relation between root yield (y) and Pi was y = 100 (0.99886)Pi - 100, and the tolerance limit was 100 eggs/100 g soil. 相似文献
12.
Measurements of second-stage juveniles of Heterodera schachtii from California and The Netherlands and a race of H. trifolii from The Netherlands were obtained and compared to determine if these populations can be differentiated by morphometrics. Juvenile lengths of 10 specimens from each of 10 cysts of each population were measured. Dimensions of tail regions of 20 juveniles from individual cysts of H. schachtii (California) and a like number of juveniles of H. trifolii (The Netherlands) were also obtained. The mean lengths of juveniles of H. schachtii from California and The Netherlands were not significantly different, but similar measurements of H. schachtii and H. trifolii were different (P = 0.05). Mean dimensions of tail lengths, tail widths, tail hyaline lengths, and tail length/tail width were significantly greater for H. trifolii than for H. schachtii. Also, dimensions of eggs of H. trifolii were significantly greater than dimensions of H. schachtii eggs. The investigations established that H. schachtii can be readily differentiated from H. trifolii by morphometrics of eggs and juveniles, Minimum sample sizes required for specified confidence intervals for each criterion measured are provided. 相似文献
13.
A. E. Steele 《Journal of nematology》1973,5(2):81-84
Cysts of Heterodera schachtii were treated in a water bath at constant temperatures ranging from 45 - 62.5 C for 1 sec to 28 hr. Treated and untreated cysts were incubated 8 weeks in sugarbeet root diffusate at 24 C to measure emergence of surviving larvae. Within the temperature range of 49 - 54 C, the minimum lethal temperature was proportional to the log time of treatment. No larvae emerged from cysts exposed 10 sec at 60 C. Although treatment of cysts for 8 hr at 45 C significantly reduced emergence, increasing the treatment period to 28 hr did not completely suppress emergence. 相似文献
14.
G. D. Griffin 《Journal of nematology》1985,17(4):385-388
Invasion of tomato (Lycopersicon esculentum L.) roots by combined and sequential inoculations of Meloidogyne hapla and a tomato population of Heterodera schachtii was affected more by soil temperature than by nematode competition. Maximum invasion of tomato roots, by M. hapla and H. schachtii occurred at 30 and 26 C, respectively. Female development and nematode reproduction (eggs per plant) of M. hapla was adversely affected by H. schachtii in combined inoculations of the two nematode species. Inhibition of M. hapla development and reproduction on tomato roots from combined nematode inoculations was more pronounced as soil temperature was increased over a range of 18-30 C and with prior inoculation of tomato with H. schachtii. M. hapla minimally affected H. schachtii female development, but there was significant reduction in the buildup of H. schachtii when M. hapla inoculation preceded that of H. schachtii by 20 days. 相似文献
15.
Aqueous solutions of 5-500 μg/ml aldicarb inhibited hatching of Heterodera schachtii. Addition of hatching agents, zinc chloride, or sugarbeet root diffusate, to the aldicarb solutions did not decrease the inhibition of hatching. When cysts were removed from the aldicarb solufions and then treated for 4 wk in sugarbeet root diffusate, larvae hatched and emerged. Treatments of newly hatched larvae of H. schachtii with 5-100 μg/ml aldicarb depressed later development of larvae on sugarbeet (Beta vulgaris). Similar treatments with aldicarb sulfoxide had less effect on larval development, and aldicarb sulfone had no effect. Numbers of treated larvae that survived and developed were inversely proportional to concentration (0.1-5.0 μg/ml) and duration (0-14 days) of aldicarb treatments. Development of H. schachtii on sugarbeet grown in aldicarb-treated soil was inversely proportional to the concentration of aldicarb in the tested range of 0.75 - 3.0 μg aldicarb/g of soil. Transfer of nematode-infected plants to soil with aldicarb retarded nematode development, whereas transfer of plants first grownin treated soil to nematode-infested soil only slightly suppressed nematode development. Development of H. schachtii was inhibited in slices of storage roots of table beet (B. vulgaris), sugarbeet and turnip, (Brassica rapa), that had grown in soil treated with aldicarb. 相似文献
16.
Arnold E. Steele 《Journal of nematology》1976,8(1):23-25
The rate of hatching of Heterodera schachtii larvae was greatly increased by placing cysts in sieves enclosed by small disposable cups. An apparatus that permitted rapid storage of second-stage larvae at 10 C prolonged the viability of the larvae. 相似文献
17.
Aqueous solutions of technical-grade phenamiphos [ethyl 3-methyl-4-(methylthio) phenyl (1-methylethyl) phosphoratnidale] were used in hatching chambers to test, under laboratory tory conditions, the effect of phenamiphos on the hatching and movement of Meloiclogyne javanica and Heterodera schachtii. Hatch of M. javanica and H. schachtii eggs was depressed 70 and 88% by nematicide at 0.48 and 4.80 μg/ml, respectively. The infectivity of second-stage larvae of both species was affected by concentrations as low as 0.01 μg/ml. At least 0.5 μg/ml was required to decrease the movement of larvae of M. javanica and H. schachtii. To decrease the movement of H. schachtii males toward females, 10 μg/ml was required. In a field experiment using a 15% granular formulation, 5 kg/ha a.i. significantly reduced infection of sugarbeet roots by H. schachtii. 相似文献
18.
Arnold E. Steele 《Journal of nematology》1983,15(3):467-473
Aldicarb, carbofuran, fensulfothion, and phenamiphos were tested in concentrations of 1-100 μg/ml for their effects on hatching of Heterodera schachtii. Exposure of cysts to 1 μg aldicarb or carbofuran/ml stimulated hatch whereas phenamiphos and, to a lesser degree, fensulfothion inhibited hatch. Addition of aldicarb to sugarbeet root diffusate or 4 mM zinc chloride suppressed activities of these hatching agents. Transfer of cysts previously treated with aldicarb or carbofuran to zinc chloride or water rapidly initiated hatch which finally exceeded the hatch from cysts not treated with the nematicides. 相似文献
19.
Fifty-four susceptible soybean, Glycine max, cultivars or plant introductions were evaluated for tolerance to H. glycines, the soybean cyst nematode (SCN). Seed yields of genotypes were compared in nematicide-treated (1,2-dibromo-3-chloropropane, 58 kg a.i./ha) and nontreated plots at two SCN-infested locations over 3 years. Distinct and consistent levels of tolerance to SCN were observed among soybean genotypes. PI 97100, an introduction from Korea, exhibited the highest level of tolerance with an average tolerance index ([yield in nontreated plot ÷ yield in nematicide-treated plot] × 100) of 96 over 2 years. Coker 156 and Wright had moderate levels of tolerance (range in index values 68 to 95) compared to the intolerant cuhivars Bragg and Coker 237 (range in index values 33 to 68). Most of the soybean genotypes evaluated were intolerant to SCN. The rankings of five genotypes for tolerance to SCN and Hoplolaimus columbus were similar. Tolerance for seed yield was more consistently correlated with tolerance for plant height (r = 0.55 to 0.64) than for seed weight (r = 0.23 to 0.65) among genotypes. 相似文献
20.
G. D. Griffin 《Journal of nematology》1988,20(3):396-404
A direct relationship exists between soil temperature and Heterodera schachtii development. The average developmental period of two nematode populations from Lewiston, Utah, and Rupert, Idaho, from J2 to J3, J4, adult, and the next generation J2 at soil temperatures of 18-28 C were 100, 140,225, and 399 degree-days (base 8 C), respectively. There was a positive relationship (P < 0.05) between nematode Pi, nematode generations, and sugarbeet yields. The greatest sugarbeet growth inhibition (87%) occurred when sugarbeets were exposed to a Pi of 12 eggs/cm³ soil for five generations (1,995 degree-days), compared with a 47% inhibition when plants were exposed to the same Pi for two generations. There was a negative correlation (P < 0.05) between the Pi, Pf, and sugarbeet yield for each population threshold. The smaller the Pi, the greater the sugarbeet yields and the greater the Pf. Root yields were 80 and 29 t /ha and Pf were 8.4 and 3.6 eggs/cm³ soil when sugarbeet seeds were planted at Pi of 0.4 and 7.9 eggs/cm³. respectively, at a soil temperature of 8 C. The number of years rotation with a nonhost crop required to reduce the nematode population density below a damage threshold level of 2 eggs/cm³ depends on the Pi. A Pi of 33.8 eggs/cm³ soil required a 5-year crop rotation, whereas a Pi of 8.4 eggs/cm³ soil required a 2-year crop rotation. 相似文献